相似子串 bzoj3230

http://www.lydsy.com/JudgeOnline/problem.php?id=3230

后缀数组

#include <iostream>#include <cstdio>#include <cstdlib>#include <cmath>#include <queue>#include <algorithm>#include <vector>#include <cstring>#include <stack>#include <cctype>#include <utility>   #include <map>#include <string>  #include <climits> #include <set>#include <string>    #include <sstream>#include <utility>   #include <ctime>#include <bitset>#include <iomanip>//#pragma comment(linker, "/STACK:102400000,102400000")using std::priority_queue;using std::vector;using std::swap;using std::stack;using std::sort;using std::max;using std::min;using std::pair;using std::map;using std::string;using std::cin;using std::cout;using std::set;using std::queue;using std::string;using std::stringstream;using std::make_pair;using std::getline;using std::greater;using std::endl;using std::multimap;using std::deque;using std::unique;using std::lower_bound;using std::random_shuffle;using std::bitset;using std::upper_bound;using std::multiset;using std::ios;using std::make_heap;using std::push_heap;using std::pop_heap;typedef long long LL;typedef unsigned long long ULL;typedef unsigned UN;typedef pair<ULL, ULL> PAIR;typedef multimap<int, int> MMAP;typedef long double LF;const int MAXN(100010);const int MAXM(310);const int MAXE(310);const int MAXK(6);const int HSIZE(13131);const int SIGMA_SIZE(26);const int MAXH(18);const int INFI((INT_MAX-1) >> 1);const ULL BASE(31);const LL LIM(1e13);const int INV(-10000);const int MOD(1000000007);const double EPS(1e-7);const LF PI(acos(-1.0));template<typename T> inline void checkmax(T &a, T b){if(b > a) a = b;}template<typename T> inline void checkmin(T &a, T b){if(b < a) a = b;}template<typename T> inline T ABS(const T &a){return a < 0? -a: a;}int Log[MAXN];void initLog(){Log[0] = -1;for(int i = 1; i < MAXN; ++i)Log[i] = (i&(i-1))? Log[i-1]: Log[i-1]+1;}struct SA{char S[MAXN];int sa[MAXN],t1[MAXN], t2[MAXN], cnt[MAXN], len, M;void init(int tl, int tm = 128){len = tl;M = tm;int *p1 = t1, *p2 = t2;for(int i = 0; i < M; ++i) cnt[i] = 0;for(int i = 0; i <= len; ++i) ++cnt[p1[i] = S[i]];for(int i = 1; i < M; ++i) cnt[i] += cnt[i-1];for(int i = len; i >= 0; --i) sa[--cnt[p1[i]]] = i;int temp = 1;for(int k = 1; temp <= len; k <<= 1){temp = 0;for(int i = len-k+1; i <= len; ++i) p2[temp++] = i;for(int i = 0; i <= len; ++i)if(sa[i] >= k) p2[temp++] = sa[i]-k;for(int i = 0; i < M; ++i) cnt[i] = 0;for(int i = 0; i <= len; ++i) ++cnt[p1[p2[i]]];for(int i = 1; i < M; ++i) cnt[i] += cnt[i-1];for(int i = len; i >= 0; --i) sa[--cnt[p1[p2[i]]]] = p2[i];swap(p1, p2);temp = 1;p1[sa[0]] = 0;for(int i = 1; i <= len; ++i)p1[sa[i]] = p2[sa[i-1]] == p2[sa[i]] && p2[sa[i-1]+k] == p2[sa[i]+k]? temp-1: temp++; M = temp;}}int rank[MAXN], hei[MAXN]; void getHei(){int k = 0;for(int i = 0; i <= len; ++i) rank[sa[i]] = i;for(int i = 0; i < len; ++i){if(k) --k;int j = sa[rank[i]-1];while(S[i+k] == S[j+k]) ++k;hei[rank[i]] = k;}}int dp[MAXH][MAXN];void initRMQ(){for(int i = 1; i <= len; ++i)dp[0][i] = hei[i];for(int i = 1; (1 << i) <= len; ++i)for(int j = 1; j+(1 << i)-1 <= len; ++j)dp[i][j] = min(dp[i-1][j], dp[i-1][j+(1 << (i-1))]);}int lcp(int a, int b){if(a == b) return len-a;a = rank[a];b = rank[b];if(a > b) swap(a, b);++a;int temp = Log[b-a+1];return min(dp[temp][a], dp[temp][b-(1 << temp)+1]);}} sa1, sa2;LL rec[MAXN];int main(){initLog();int n, Q;scanf("%d%d", &n, &Q);scanf("%s", sa1.S);for(int i = 0; i < n; ++i) sa2.S[i] = sa1.S[n-i-1];sa2.S[n] = '\0';sa1.init(n);sa2.init(n);sa1.getHei();sa2.getHei();sa1.initRMQ();sa2.initRMQ();for(int i = 1; i <= n; ++i) rec[i] = rec[i-1]+(n-sa1.sa[i]-sa1.hei[i]);LL q1, q2;for(int i = 0; i < Q; ++i){scanf("%lld%lld", &q1, &q2);int i1 = lower_bound(rec, rec+1+n, q1)-rec;int i2 = lower_bound(rec, rec+1+n, q2)-rec;if(i1 > n || i2 > n){printf("-1\n");continue;}int l1 = (n-sa1.sa[i1])-(rec[i1]-q1);int l2 = (n-sa1.sa[i2])-(rec[i2]-q2);LL a = min(sa1.lcp(sa1.sa[i1], sa1.sa[i2]), min(l1, l2));LL b = min(sa2.lcp(n-1-(sa1.sa[i1]+l1-1), n-1-(sa1.sa[i2]+l2-1)), min(l1, l2));printf("%lld\n", a*a+b*b);}return 0;}